<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>

    <script>
        function fn(a) {
            console.log(a);
            var a = 2;
            function a() {};
            // var a = function() {};
            console.log(a);
        }

        fn(1);
        a();
    </script>
</body>
</html>